Role of Topology on Properties of a Two-Dimensional Catenated DNA Network

The topology of polymer molecules plays an important role in determining their physical properties. Tuning the topology of molecules is thus imperative in controlling the physiochemical properties tailored for desired applications. We studied herein the role of topology on the static and dynamic properties of a two-dimensional (2D) catenated network of DNA rings called a kinetoplast. A kinetoplast is a catenated DNA network of thousands (~ 5000) of rings and presents a robust model system to study the physical properties of 2D polymers and Olympic gels. The heterogeneity in base pair sequencing of different classes of rings within the kinetoplast network and the precise action of restriction enzymes have been harnessed to tune the topology of the kinetoplast network. We find that irrespective of topology the spatial extension of the network remains invariant, however, it significantly affects the shape fluctuations of the network. Irrespective of details of the molecular topology, the relationship between the time constant of thermal relaxation and variance of shape anisotropy shows a universal scaling. Our results provide a route to selectively tune the elastic properties of 2D catenated DNA networks by modifying the underlying topology.